1B - Single - hits on which the batter reached first base safely without the contribution of a fielding error.

2B - Double - hits on which the batter reached second base safely without the contribution of a fielding error.

3B - Triple - hits on which the batter reached third base safely without the contribution of a fielding error.

AB - At bat - Batting appearances, not including bases on balls, hit by pitch, sacrifices, interference, or obstruction

AB/HR At bats per home run - at bats divided by home runs

BA - Batting average (also abbreviated AVG) - hits divided by at bats

BB - Base on balls (also called a "walk") - times receiving four balls and advancing to first base

BABIP Batting average on balls in play - frequency of which a batter reaches a base after putting the ball in the field of play. Also a pitching category.

BB/K - Walk-to-strikeout ratio - number of base on balls divided by number of strikeouts

XBH - Extra base hits - doubles plus triples plus home runs

FC - Fielder's choice - times reaching base when a fielder chose to try for an out on another runner

GO/AO - Ground ball fly ball ratio - number of ground ball outs divided by number of fly ball outs

GDP or GIDP - Ground into double play - number of ground balls hit that became double plays

GPA - Gross Production Average - 1.8 times on-base percentage plus slugging percentage, divided by four

GS - Grand Slam - a home run with the bases loaded, resulting in four runs scoring, and four RBI credited to the batter.

H - Hits - times reached base because of a batted, fair ball without error by the defense

HBP - Hit by pitch - times touched by a pitch and awarded first base as a result

HR - Home runs - hits on which the batter successfully touched all four bases, without the contribution of a fielding error.

IBB - Intentional base on balls - times awarded first base on balls (see BB above) deliberately thrown by the pitcher. Also known as IW (intentional walk).

K - Strike out - number of times that strike three is taken or swung at and missed, or bunted foul

LOB - Left on base - number of runners not out nor scored at the end of an inning.

OBP - On base percentage - times reached base (H + BB + HBP) divided by at bats plus walks plus hit by pitch plus sacrifice flies (AB + BB + HBP + SF).

OPS - On-base plus slugging - on-base percentage plus slugging average

PA - Plate appearance - number of completed batting appearances

RC - Runs created - statistic that attempts to measure how many runs a player has contributed to his team

RP - Runs produced - statistic that attempts to measure how many runs a player has contributed

RBI - Run batted in - number of runners who scored due to a batters' action, except when batter grounded into double play or reached on an error

RISP - Runner In Scoring Position - the batter's batting average with runners in scoring position

SF - Sacrifice fly - number of fly ball outs to the outfield which allow a runner already on base to score

SH - Sacrifice hit - number of sacrifice bunts which allows another runner to advance on the basepaths or score

SLG - Slugging average - total bases divided by at-bats

TA - Total average - total bases, plus walks, plus hit by pitch, plus steals, minus caught stealing divided by at bats, minus hits, plus caught stealing, plus grounded into double play

TB - Total bases - one for each single, two for each double, three for each triple, and four for each home run

TOB - Times on base - times reaching base as a result of hits, walks, and hit-by-pitches

BsR - Base Runs - Another run estimator, like Runs Created; a favorite of writer Tom Tango

XR - Extrapolated Runs - A linear run estimator developed by Jim Furtado

 Baserunning statistics

CS - Caught stealing - times tagged out while attempting to steal a base

SB - Stolen base - number of bases advanced other than on batted balls, walks, or hits by pitch

• DI - Defensive Indifference - if the catcher does not attempt to throw out a runner (usually because the run would be insignificant), the runner is not awarded a steal

R - Runs scored - times reached home base legally and safely

 Pitching statistics

BB - Base on balls (also called a "walk") - times pitching four balls, allowing the batter-runner to advance to first base

BB/9 - Base on balls times nine divided by innings pitched (Bases on balls per 9 innings pitched)

BF - Total batters faced - opponent's total plate appearances

BK - Balk - number of times pitcher commits an illegal pitching action or other illegal action while in contact with the pitching rubber, thus allowing baserunners to advance

BS - Blown save - number of times entering the game in a save situation, and being charged the run (earned or not) which eliminates his team's lead

CERA - Component ERA - an estimate of a pitcher's ERA based upon the individual components of his statistical line (K, H, 2B, 3B, HR, BB, HBP)

CG - Complete game - number of games where player was the only pitcher for his team

DICE - Defense-Independent Component ERA - an estimate of a pitcher's ERA based upon the defense-independent components of his statistical line (K, HR, BB, HBP)

ER - Earned run - number of runs that did not occur as a result of errors or passed balls

ERA - Earned run average - total number of earned runs (see "ER" above), multiplied by 9, divided by innings pitched

ERA+ - Adjusted ERA+ - earned run average adjusted for the ballpark and the league average

G - Games (aka 'appearances') - number of times a pitcher pitches in a season

GF - Games finished - number of games pitched where player was the final pitcher for his team

G/F - Ground ball fly ball ratio - ground balls allowed divided by fly balls allowed

GS - Starts - number of games pitched where player was the first pitcher for his team

H/9 - Hits per nine innings - hits allowed times nine divided by innings pitched (also known as H/9IP - Hits allowed per 9 innings pitched)

H - Hits Allowed - total hits allowed

HB - Hit batsman - times hit a batter with pitch, allowing runner to advance to first base

HLD (or H) - Hold - number of games entered in a save situation, recorded at least one out, did not surrender the lead, and did not complete the game

HR - Home runs allowed - total home runs allowed

IBB - Intentional base on balls allowed

IP - Innings pitched - number of outs recorded while pitching divided by three

IP/GS - Average number of innings pitched per game

IR - Inherited runners - number of runners on base when the pitcher enters the game

IRA - Inherited runs allowed - number of inherited runners allowed to score

K - Strikeout - number of batters who received strike three

K/9 - Strikeouts per nine innings - strikeouts times nine divided by innings pitched (Strikeouts per 9 innings pitched)

K/BB - Strikeout-to-walk ratio - number of strikeouts divided by number of base on balls

L - Loss - number of games where pitcher was pitching while the opposing team took the lead, never lost the lead, and went on to win

OBA - Opponents batting average - hits allowed divided by at-bats faced

PIT - Pitches thrown (Pitch count)

QS - Quality start - a game in which a starting pitcher completes at least six innings and permits no more than three runs

RA - Run average - number of runs allowed times nine divided by innings pitched

R.R.A - Relief Run Average - A function of how many inherited base runners a relief pitcher allowed to score.

SHO - Shutout - number of complete games pitched with no runs allowed

SO - Strikeout Also may be notated as 'K'.

SV - Save - number of games where the pitcher enters a game led by the pitcher's team, finishes the game without surrendering the lead, is not the winning pitcher, and either (a) the lead was three runs or less when the pitcher entered the game; (b) the potential tying run was on base, at bat, or on deck; or (c) the pitcher pitched three or more innings

W - Win - number of games where pitcher was pitching while his team took the lead and went on to win (also related: winning percentage)

WHIP - Walks and hits per inning pitched - average number of walks and hits allowed by the pitcher per inning

WP - Wild pitches - charged when a pitch is too high, low, or wide of home plate for the catcher to field, thereby allowing one or more runners to advance or score

 Fielding statistics

A - Assists - number of outs recorded on a play where a fielder touched the ball, except if such touching is the putout

DP - Double plays - one for each double play during which the fielder recorded a putout or an assist.

E - Errors - number of times a fielder fails to make a play he should have made with common effort, and the offense benefits as a result

FP - Fielding percentage - total plays (chances minus errors) divided by the number of total chances

INN - Innings - number of innings that a player is at one certain position

PB - Passed ball - charged to the catcher when the ball is dropped and one or more runners advance

PO - Putout - number of times the fielder tags, forces, or appeals a runner and he is called out as a result

RF - Range factor - ([putouts + assists]*9)/innings played. Used to determine the amount of field that the player can cover

TC - Total chances - assists plus putouts plus errors

TP - Triple play - one for each triple play during which the fielder recorded a putout or an assist

 General statistics

G - Games played - number of games where the player played, in whole or in part

Pythagorean expectation - estimates a team's expected winning percentage based on runs scored and runs allowed.